GM crops linked to monarch butterfly decline

Published today in the Journal of Animal Ecology, our paper demonstrates that the widespread planting of GM crops across the mid US is likely driving the current decline of monarch butterflies, not climate change or habitat loss in its overwintering grounds in Mexico as previously thought. The impact of GM crops is indirect through the spraying of ‘Round-up’ ready crops causing the loss of milkweed – monarchs primary food source and larval host plant. This paper presents the first year-round multi-generational matrix population model for a migratory insect and is a big step forward in modelling the dynamics of migratory species. Led by my PhD student Tyler Flockhart, this was a collaboration between CSIRO (Jean-Baptiste Pichancourt and myself) and University of Guelph (Tyler and Ryan Norris).